The present invention is a process for treating a plurality of by-product streams containing chlorosilicon compounds. The process comprises the steps of determining the average SiCl functionality of a plurality of by-product streams comprising chlorosilicon compounds, blending at least two of the by-product streams to form a blended by-product stream having an average SiCl functionality greater than or equal to 2.8, adding to the blended by-product stream a surfactant having a HLB number within a range of about 3 to 28, and contacting the blended by-product stream with an aqueous medium at a temperature within a range of about 50.degree. C. to 120.degree. C. to form a granular siloxane gel.
Danielson et al., U.S. Pat. No. 4,221,691, teach that the addition of a relatively small amount of a hydrocarbon oil to a polyfunctional chlorosilicon composition prior to hydrolysis significantly improves the handling characteristics of the siloxane gel that is obtained. The term "polyfunctional chlorosilicon composition" was defined as "compositions containing a major proportion of chlorosilicon compounds with at least 3 chlorine radicals bonded to silicon per molecule". The method of Danielson et al., can not be used to successfully hydrolyze many of the by-product or waste streams of a commercial silicone plant to obtain a handleable gel since many of these streams may not contain sufficient polyfunctional chlorosilicon compounds. Furthermore, adding a hydrocarbon oil could present an additional expense in the waste treatment process.
Marko, U.S. Pat. No. 4,408,030, describes a process for treating a plurality of streams containing chlorosilicon compounds to obtain a solid siloxane material or gel that is easily handleable, however the gels may sink, float and/or stay suspended in the aqueous acid phase making separating the gels difficult.
Degen et al., U.S. Pat. Nos. 4,960,523 and 4,961,861 describe a process for working up the high-boiling, solids-containing residues obtained in the synthesis of organochlorosilanes which are hydrolyzed and then oxidized, comprising adding during hydrolysis and/or oxidation a surface-active agent which hydrophilicizes the surface of the solids.
The present invention provides a process for treating a plurality of by-product streams containing chlorosilicon compounds to produce a siloxane gel that is easily handleable, has a finer more uniform particle size, and floats on the liquid surface making the granular siloxane gel readily separable from the liquid phase than gels previously described. Furthermore, the present invention provides a process by which diverse by-product streams of a commercial silicone plant can be economically hydrolyzed to greatly reduce the chlorine content prior to disposal. Finally, the present invention provides a process for treating by-product chlorosilicon streams whereby hydrogen chloride may be recovered.